The present invention relates to an optical disk player and, more particularly, to an optical disk player having a phase adjusting device for correcting a phase error.
An optical disk player records and reproduces audio and video data on and from a recording medium such as an optical disk including a compact disk (CD), a laser disk, and a digital video disk (DVD) using an optical pickup. The optical disk player is widely used as an auxiliary memory device for a computer and an audio and video reproducing device. The optical pickup of the optical disk player reciprocates over a rotating optical disk to record information thereon or reproduce the recorded information from pits formed thereon.
Referring to FIG. 1, an optical disk player 10 has a deck 11, a turntable 12 for loading an optical disk D thereon, a driving motor 19 for rotating the turntable 12, an optical pickup 15 for linearly reciprocating across the deck 11, guide shafts 13a and 13b for guiding the optical pickup 15, an optical pickup driving motor 16 for transferring the optical pickup 15, and a transmission unit for converting the rotation of the optical pickup driving motor 16 into a linear movement.
There may be many variations of the transmission unit. In the embodiment of FIG. 1, the transmission unit comprises a pinion gear 16a attached to a rotating shaft of the optical pickup driving motor 16, an idler gear 17 engaged with the pinion gear 16a, and a rack 15a formed on a side of the optical pickup 15, by which the optical pickup 15 can be moved linearly. Bushings 14 for supporting the guide shafts 13a and 13b are fixed on the deck 11. The optical pickup 15 is guided along the guide shafts 13a and 13b on the deck 11.
To densely record data and reproduce data in the optical disk player as constituted above, the relative position between the optical pickup 15 and the optical disk D should be kept uniformly while the optical pickup 15 is being transferred along the guide shafts 13a and 13b.
Generally, the transfer of the optical pickup 15 experiences three kinds of phase errors. When the optical pickup 15 is not transferred along the radial direction of the optical disk D, a horizontal phase error is produced. When the optical pickup 15 is not parallel to the plane of the optical disk D such that the optical pickup 15 is tilted in the tangential direction or the radial direction of the optical disk D, tilt phase errors of the tangential or radial directions occur, respectively. Since the optical pickup 15 is transferred along the guide shafts 13a and 13b supported on the deck 11 by the bushings 14, the installation direction and inclination of the guide shafts 13a and 13b directly influence the phase errors. That is, inaccurate installation of the guide shafts 13a and 13b deteriorates the quality of a signal recorded on or read from the optical disk D. Therefore, a phase adjusting device is required to adjust the installation of the shafts 13a and 13b on the deck 11.
In the general optical disk player of FIG. 1, no phase adjusting device is provided and the installation state of the optical pickup 15 is determined by the accuracy of the machining and assembly of the bushings 14 or the shafts 13a and 13b. Therefore, unless each part is precisely machined and parts are well assembled, the optical pickup 15 cannot be reliably transferred. In particular, even if the machining of parts and assembly management are performed within set tolerances, correction of the phase errors is difficult due to the accumulation of the errors.